docs: def kld(d1, d2):
      """Return the Kullback-Leibler Divergence (KLD) between two distributions.
  
      Args:
          d1 (np.ndarray): The first distribution.
          d2 (np.ndarray): The second distribution.
  
      Returns:
          float: The KLD of ``d1`` from ``d2``.
      """
      d1, d2 = flatten(d1), flatten(d2)
      return entropy(d1, d2, 2.0)